This application is to develop the San Diego Hospital Influenza Immunization Partnership (SDHIIP) by building on the very strong collaborative environment in County of San Diego between the County of San Diego Health and Human Services Agency Immunization Branch (HHSA Immunization Branch) and local hospitals to improve hospital-based health care worker (HCW) influenza immunization rates. The investigators for this proposal, the directors of the San Diego Immunization Partnership, are under contract to and co-located at the County of San Diego HHSA Immunization Branch offices. Goal 1: Share best practices for influenza immunization of HCW among all of the major hospital systems in San Diego County. Goal 2: Facilitate the implementation of new interventions to improve HCW influenza immunization in all of the participating hospital systems. Goal 3: Document HCW influenza immunization coverage rates and HCW attitudes and beliefs concerning influenza immunization at all of the participating institutions. Goal 4: Share HCW influenza immunization coverage rates as well as analyses of each intervention attempted to improve coverage rates between all participating institutions. Goal 5: Estimate the costs and cost-effectiveness of each hospital's HCW influenza immunization program. [unreadable] [unreadable]